The Treatment of Patients With Irritable Bowel Syndrome: Review of the Latest Data From the 2010 DDW Meeting.

6 Gastroenterology & Hepatology Volume 6, Issue 7, Supplement 10 July 2010 18 years of age and for travelers’ diarrhea caused by noninvasive strains of Escherichia coli in patients older than 12 years of age. Ongoing studies are currently investigating rifaximin in IBS. A recent phase IIb multicenter clinical trial found that rifaximin effectively provided relief of global IBS symptoms such as bloating and improved quality of life in patients with diarrhea and mixed IBS.7,8 Here, 2 identically designed phase III, randomized, double-blind, placebo-controlled, multicenter clinical trials (TARGET 1 and TARGET 2) evaluated the efficacy of rifaximin in nonconstipated IBS patients. In these 2 phase III studies, a total of 1,260 patients (TARGET 1, n=623; TARGET 2, n=637) with mild-to-moderate symptoms of nonconstipated IBS symptoms were randomized to receive 550 mg of rifaximin 3 times a day or a placebo for 2 weeks. Responses were measured during a 10-week follow-up period, with the primary endpoint being the percentage of patients who were responders in the intent-to-treat (ITT) population. Patients were considered responders if they had adequate relief of weekly IBS symptoms for 2 or more of the first 4 weeks immediately following the 2-week treatment period. The rifaximin and placebo groups did not differ in terms of baseline demographics in the TARGET 1, TARGET2, or pooled study analyses. A significantly greater percentage of patients in the rifaximin group were responders compared with the placebo group in both TARGET trials and in the pooled analysis. In addition, a significantly higher proportion of patients taking rifaximin had IBS symptom relief compared to patients given a placebo (Table 1; TARGET 1, P=.0125; TARGET 2, P=.0263; Pooled, P=.0008). Adequate relief of bloating, a key secondary endpoint, was also met by significantly more patients in the rifaximin group compared to the placebo group (Table 1; TARGET 1, P=.0045; TARGET 2, P=.0167; Pooled, P=.0002). Patients taking rifaximin also had significantly improved daily assessments of IBS symptoms, bloating, abdominal pain, and discomfort, all of which were additional secondary endpoints. As independent studies and in a pooled analysis, TARGET 1 and TARGET 2 both reported a significantly higher likelihood of sustained IBS symptom relief during the 3-month study period in patients taking rifaximin compared to those given a placebo. Additionally, the safety profile of rifaximin was similar to the placebo. Based on the combined results of TARGET 1 and TARGET 2, the authors concluded that 550 mg of oral rifaximin taken 3 times daily for 14 days is significantly more effective than placebo in achieving adequate relief of IBS symptoms. Furthermore, rifaximin is significantly more likely to provide acute and sustained symptom relief of IBS symptoms over a 12-week period. Patients Not Responding to Antibiotics Have Secondary Causes of Symptoms S1326: Presumed IBS Subjects With Short Remission After Antibiotic Therapy Often Have Secondary Causes for Their Symptoms9 Jim Y. Chou, Robert Tabrizi, Mark Pimentel,